The present invention is directed generally to lifting mechanisms and, more particularly, to a method and apparatus for engaging and lifting trays and loading the trays into a shipping container.
Many repetitive tasks have been automated to reduce labor costs and to increase efficiency of manufacturing. For example, assembly lines often arc designed to lift components of an article of manufacture and move the components to a position where the components are incorporated into the article of manufacture. One example of such automation is an automobile assembly line where components of the automobile are automatically lifted and positioned along the assembly line at a location where the various components will be added to the automobile under assembly.
In other circumstances, components may not be easily moved through automatic means. For example, trays of components must be carefully lifted and moved so as not to tip over the trays and drop the components. One such mechanism for lifting trays of components is illustrated in U.S. Pat. No. 5,690,467, which is designed to lift trays of electrical components. As described in that patent, a lifting mechanism grasps the tray from the side and has hydraulically controlled pawls that extend underneath the tray to provide the necessary lifting capability. While such an approach is useful for lifting trays of components, this mechanism does not lend itself to an automated process for loading the trays of components into a carton or other shipping container. In a desired loading operation, the trays are sized to fit in the carton without excessive room in the carton such that the trays would shift from side to side. However, the requirements of a snug fit between the side of the tray and the carton makes the system described in the above-referenced patent unfeasible since excess room would be required in the carton to allow the lifting pawls to engage the tray at its sides.
Therefore, it can be appreciated that there is a significant need for an apparatus and method that would allow trays to be lifted and automatically placed in a carton or shipping container. The present invention provides this and other advantages as will be described by the following detailed description and accompanying figures.
The present invention is embodied for loading trays and comprises a motor and a drive mechanism coupled to the motor. A plurality of rotatable engagement members is coupled to the drive mechanism and rotated in a first direction in response to motor movement in a first direction. The engagement members engage and retain a tray when rotated in the first direction. A lift mechanism raises and lowers the engagement members after the engagement members have engaged and retained the tray to thereby move the tray.
In one embodiment, the engagement members have an auger-shaped member to engage and retain the tray. The system also includes position detectors to control the positioning of the elements. A limit sensor may be positioned proximate the drive system to detect movement thereof and to allow a predetermined amount of rotational movement of the engagement members. A limit sensor may also be positioned proximate the lift mechanism to determine vertical movement thereof to allow a predetermined amount of vertical movement of the engagement members. In one embodiment, a computer control system is preprogrammed with data relating to the size of the trays and uses the data to determine the amount of vertical movement of the engagement members to deposit a tray into a shipping carton.